honestly, if your natural periods are that irregular, you have fertility problems. I'm sorry, but you should get a complete fertility workup, including a hormone panel, thyroid test, and blood suger/insulin test to check for PCOS.
A normal, healthy, fertile woman does not have irregular periods the way you describe. Honestly, if your gyn knows you are ttc, with your history, and hasn't talked to you about the possibility of infertility, that's almost criminal.

I also had fertility issues, and it took us 4 years to get prego the first time.

The main causes of infertility in women are PCOS, thyroid problems, endometriosis, and PID. Unless you know for sure you don't have any of these conditions, a trip to the doc is in order, preferably an infertility specialist, if you normal gyn does not have experience in the area.

I don't know nearly as much about endo or pid, since i dont have those, but i do have pcos and thyroid, so I'd be happy to discuss those with you if you want.